1. Field of the Invention
The present invention generally relates to a bracket for securing a traffic control device to a mast arm, pole or other support. More particularly, the present invention is directed to a traffic control device securing bracket comprising a bracket clamp plate and mast arm anchor plate having telescopically engageable tubular sections capable of being axially secured after being placed in telescopic engagement without requiring access from either end of the tubular sections.
2. Description of the Background
Traffic signal lights are typically secured to a horizontally or vertically extending mast arm, pole or other support using a two part bracket. For ease in discussion, the term "mast arm" hereinafter shall refer to any mast arm, pole or other support disposed at any angle. The construction of these securing brackets and the means for adjusting and fixing the orientation of the two parts have developed over the years.
The earliest prior art brackets were simple devices comprising a first clamp for attachment to the traffic control device and a second clamp for attachment to the mast arm. The attached clamps were then screwed, bolted or otherwise fixed together in the desired orientation. U.S. Pat. No. 4,489,910 to Ferguson illustrates a simple bracket of this type capable of securing an electric traffic signal device to a mast arm. Other simple devices of this type are illustrated in U.S. Pat. Nos. 4,860,985 and 4,917,338 to Olson. The devices disclosed by Ferguson and Olson permitted adjustment of the relative orientation of the mast arm and control device bracket portions only through relatively small angles, e.g., about 55 degrees, by use of a conventional slot and screw adjustment means. These simple clamping devices provided no enclosed conduit so that electrical conductors and connections could be aesthetically disposed out of sight within the mast arm, bracket and traffic control device.
An improved bracket was disclosed by Parduhn in U.S. Pat. Nos. 3,586,280 and 3,764,099. See particularly FIG. 2 in each of the Parduhn patents. The bracket disclosed by Parduhn included a first plate designed to engage an elongated member affixed to the traffic control device and a second plate designed to engage the mast arm. Extending from each plate was a tubular section. The tubular sections were sized to permit telescopic engagement. The telescoped tubular sections were threaded together and secured in the desired orientation by engagement of a set screw. The threaded construction disclosed by Parduhn resulted in relatively expensive brackets. Further, in use, the set screw often proved unsatisfactory to maintain the traffic control device in the desired orientation with the mast arm. Exposure to strong winds for long periods of time often resulted in loosening of the set screw which permitted the traffic control signal to rotate from the desired orientation.
While the Parduhn brackets proved unsatisfactory for the foregoing reasons, commercially available brackets similar to those disclosed in Parduhn offered the ability to conceal the electrical wiring within the mast arm, bracket and traffic control device. While the Parduhn patents make no mention of concealed electrical connection, brackets substantially identical to those disclosed in the Parduhn patents, particularly the '099 patent, were sold at least as early as 1977 by VePed Traffic Controls, Inc. of Oklahoma City, Okla. under the trademark Astro Brac. While these brackets permitted the aesthetic concealment of the electrical wiring, the threaded engagement of the telescoping members and use of a set screw to rigidly secure the orientation thereof failed to solve the previously discussed problems associated therewith.
In an attempt to solve the problems resulting from threaded interconnection of the telescopic members and the use of a set screw, an improved bracket was disclosed in U.S. Pat. No. 4,460,142 by O'Rorke. Instead of threaded interconnection of the tubular sections, O'Rorke disclosed the use of a bolt placed along the axes thereof and threaded into the mast arm end plate. While providing a less expensive bracket by eliminating the threaded connection and while providing more secure orientation by eliminating the set screw, the bracket disclosed by O'Rorke failed to make any provision for internal concealment of the electrical conductors and connectors. Further, the bracket disclosed by O'Rorke suffered from the requirement that the relative orientation of the members had to be determined and the bolt tightened before attachment of the traffic signal device to the bracket.
Still another prior art bracket attempting to solve some of the discussed problems was disclosed by Parduhn in U.S. Pat. No. 4,659,046. In the '046 patent Parduhn disclosed a bracket including tubular sections in telescopic engagement. The bracket disclosed by Parduhn in the '046 patent comprised the two basic components for engagement with the mast arm and the traffic control device. The two components included tubular sections telescopically interconnected by use of a snap ring to prevent axial separation. The snap ring was engaged through the opened end of the telescoped tubular sections. The bracket members disclosed in the '046 patent included openings through the bracket plates at the end of each tubular section to permit concealed electrical connections similar to those in the previously discussed Astro Brac bracket sold by VePed. Relative rotation of the telescoped members was permitted prior to rigid interconnection by clamping of the outer section to the inner section.
While the bracket disclosed by Parduhn in the '046 patent solved many of the prior art problems, including the expensive construction associated with threaded interconnection of the telescopic members, mounting failures resulting from loosening of the set screw and concealment of the electrical conductors, other problems remained. For example, because the snap ring had to be inserted through the open face of the mast arm plate, the bracket had to be axially secured before mounting to the mast arm. In fact, the bracket typically was sold with the plates already axially secured by the snap ring. However, in use, installers often would like to secure the individual bracket components to the mast arm and traffic signal device before telescopic engagement of those components. This procedure permits the installer or repairman to quickly install or remove the heavy traffic signal device without having to support is weight for an extended time. Accordingly, the device disclosed in the Parduhn '046 patent failed to solve all of the problems of the prior art.
Because none of the foregoing devices solved all of the problems associated with brackets for traffic control devices and because all suffered from one or more of the aforementioned deficiencies, there has been a long felt but unfulfilled need for an improved bracket for traffic control devices in which telescopically engageable tubular sections assembled to a mast arm and signal device may be quickly and easily connected or disconnected by the installer/repairman, in which the telescopically engaged sections are fully rotatable about 360 degrees and in which the electrical connections may be fully concealed within the telescopically engaged sections. No prior art bracket offers all of the foregoing advantages.